Until recently it was rather difficult to accurately detect leaks in air conditioning and refrigeration systems. Often a serviceman was required to interpret test results which were very vague and ambiguous. One method typically used was to employ a Halide torch requiring the serviceman to observe a particular color change when escaping system chlorofluorocarbon refrigerant material (e.g., FREON.RTM.) came in contact with the torch flame. Another common method available was to provide a fluorescent leak detection composition which was applied to the outer surface of a system's equipment or pipes. A composition typically used for that application is disclosed in U.S. Pat. No. 4,249,412.
Not only were those test methods hard to interpret, but they made it troublesome to pinpoint the exact source of a leak. In practice, the serviceman would have difficulty showing a customer the exact location of the leak or leaks. In many cases, the serviceman was more apt to recharge the system with additional refrigerant rather than locating and repairing the existing leak.
In more recent years, it has become common practice in the automotive air conditioning field to provide one pound cans of a pre-mixed formulation of refrigerant and fluorescent dye material to be infused into a closed loop air conditioning system. That practice allows system leaks to be reliably pinpointed when the refrigerant and fluorescent dye formulation is used in conjunction with an ultraviolet light emitting in approximately the 365 nm range. Since the closed loop is under pressure, the fluorescent dye is forced outwardly through any existing holes in the system thereby becoming clearly visible to the human eye upon application of the ultraviolet light. A method and device typical of the pre-mixed formulation system is disclosed in trade literature entitled Spectroline.RTM. Automotive Leak Detection Systems which is available through Spectronics Corporation, Westbury, N.Y.
Some advantages of infusing a pre-mixed refrigerant/fluorescent dye formulation instead of relying on the aforementioned methods include: (1) being able to accurately pinpoint the exact source of the leak or leaks; (2) being able to positively recognize the leak without having to interpret the test results; (3) being able to directly show a customer the existing leak or leaks; and (4) making it possible for the leaks to be repaired rather than just refilling the system with additional refrigerant. The importance of being able to detect and repair such leaks is two-fold. First, the efficiency of the system is reestablished following the necessary repairs, and secondly, leaking refrigerant is kept from escaping into the atmosphere, thereby minimizing the depletion of the earth's ozone layer.
However, it is impractical if not impossible to neatly and efficiently charge large commercial air conditioning and refrigeration systems with the existing pre-mixed one pound can formulations of fluorescent dye and refrigerant known in the prior art. Since such systems are closed loops operating under pressure, it has not been possible to repeatedly introduce the fluorescent dye without substantial leakage and contamination. When infusing a system with the pre-mixed formulation, it is most desirable to charge the system with as little carrier refrigerant as possible until the leak or leaks are located, because, in practice, the refrigerant is often vented to the atmosphere when repairing the leak. If any of the pre-mixed formulation is inadvertently spilled onto the system equipment during infusion, examination of the system for traces of refrigerant material becomes impossible, since spillage can mask leaks.
The use of pre-mixed one pound cans of the refrigerant and dye formulation, or even larger commercially available thirty pound cylinders of the refrigerant and dye formulation, do not allow any flexibility in the amount of dye to be added to a particular system. In large commercial air conditioning and refrigeration systems, the dye amount and concentration necessary will vary depending on the weight of the refrigerant charge of that system. Nearly all systems will be either undercharged or overcharged as a result of the use of the pre-mixed can or cylinder formulations. Therefore, if a serviceman is to effectively detect leaks in a large commercial system, various quantities of dye, in various concentrations, must be repeatedly infused into the system. As mentioned above, improperly charging a system will cause fluorescent dye to be spilled onto the system equipment or cause excess refrigerant to be vented to the atmosphere.
Additionally, commercial air conditioning and refrigeration systems use not only various amounts of refrigerant but also various types of refrigerant. Examples of commercially useful refrigerants include FREON.RTM. 11, R12, R22, 502, 500, 114, 113, 23, 116, 13, 14, 13B1, and 503. The various types of refrigerants used preclude the practical stocking and supply of the correct concentration and amount of dye formulation necessary for every particular commercial system. Many types of dyes, such as DuPont's Dytel Red Visible Dye, manufactured by the E.I. DuPont de Nemours Co., Wilmington, Delaware, are normally only stocked by distributors in pre-mixed refrigerant/dye formulations containing FREON.RTM. 11, 12 and 502.
The novel apparatus and method of the present invention overcome the foregoing deficiencies of the prior art by providing an apparatus and method for neatly and efficiently infusing a mixture of leak detection material and system carrier fluid into a closed loop system for the purpose of detecting and pinpointing leaks. The present invention accomplishes this result in a manner which minimizes the venting of system carrier fluid to the atmosphere while providing a system carrier fluid and leak detection material mixture which is appropriate for a particular sized commercial system. Accordingly, it is an object of the present invention to provide an apparatus and method for infusing a leak detection material into an operating closed loop system which does not have the inherent deficiencies of the prior art.
Other objects and advantages of the present invention will be apparent to those skilled in the art with reference to the attached drawings and the description of the invention which hereinafter follows.